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LFAM Printers Push Physical Limits.
Large-format additive manufacturing (LFAM) machine makers continue to press the laws of physics.
One just sold its biggest 3D printer ever, capable of making parts almost 20′ (6.1 m) long. Another makes an LFAM machine that can print at a 45° angle. And yet another has a new machine solely for making composite molds that prints and casts the tools at one time.
At the same time, as computing power continues to take over more operations for today’s machine tools, large-format 3D printers are no exception.
No Manual Calibration
BigRep America Inc., Wilmington, Mass., may be the latest of the LFAM machine makers to fiddle around with the brains that control the operation of one of its machines, resulting in the Pro.2. With the new model, manual calibration for the print bed, extruders and dual extruding mechanism is a thing of the past.
“If you look at it from the outside it looks exactly the same, but we really focused on ease of use,” said Marco Mattia Cristofori, head of product marketing for parent company BigRep GmbH, Berlin. “We worked a lot on the MXT control system so the computer is much smarter. The main focus is all around having the user just focusing on slicing and preparing the G code.”
The updates in the MXT system are part of BigRep’s new Jumpstart, a “hybrid software-hardware solution that lets you skip the hassle and just start printing,” according to the company’s website. Jumpstart has two more components: Switchplate, a removable and flexible print bed that snaps into place aided by magnets; and Lockstage, an aid in easy and secure extruder mounting, with the extruders also snapping into place.
The new model is supported by BigRep’s Precision Motions Portal, a custom-built gantry powered by Bosch Rexroth CNC components, including servo motors with integrated encoders.
“The portal is much lighter and can really increase accuracy and speed,” Cristofori said.
Metso Outotec, a global supplier of equipment and solutions for the mineral processing and metal refining industries, used to make molds and core boxes for metal casting by first gluing together blocks of wood. The resulting wood billet would then be milled with a CNC.
In February 2021, however, the company’s foundry in Brazil installed a BigRep Pro that has largely replaced the need for heavy wood blocks. After printing 70 parts on its Pro, Patricia Moraes, who is in charge of 3D printing at the foundry, noted Metso cut pattern costs by up to 70 percent, sped up production, made handling of the polymer patterns easier because they’re lighter than wood and freed up storage space previously reserved for wood.
Two Extruders, One Part
BigRep also recently enhanced its flagship model, the One, to produce the One.4. The One.4 is completely configurable, with single, dual and twin extruders available. The dual mode allows a user to print with water-soluble support material in the second extruder. Or they can use two materials with different mechanical properties in the extruders for more complex applications.
The same material can be used for a print and its supports, which will snap right off. But for a “radically” improved surface finish, users should look to BigRep’s water-soluble support material that completely washes away, said Tim Ruffner, sales director for the Americas. Zoeller, a waste collection vehicle manufacturer based in Germany, upgraded a One it bought in 2019 to twin extruders to increase output.
Speeding up prototype iterations with 3D printing helps with Zoeller’s need for constant adaptation to comply with country-specific safety and protection regulations for its vehicles that are used in many different countries. Because the next generation of vehicles uses mechanical lifters instead of human trash handlers, the vehicles must also be able to lift different types of bins.
Before Zoeller adopted 3D printing, components to house controls, lights and sensors had to be laboriously formed from steel sheets. In addition to taking a long time to develop, these prototypes were limited in terms of complexity, precision and material properties.
What a difference 3D printing has made for the company: prototype iterations now take days, not weeks; customers can examine changed parts quickly, while their ideas are fresh in their minds; and the printed prototypes are easy to install on vehicles, so they can be tested in real-world conditions.
Flexible Printing at 45°
In 2020, Thermwood Corp. and General Atomics Aeronautical Systems Inc. competed in a head-to-head comparison of two additive manufacturing methods to make a CNC trim tool.
The aerospace company used a hand layup process to make the carbon fiber laminate trim tool that’s used to hold another mold or tool while it’s being machined. Thermwood 3D printed an 1,190 lb (539.77 kg) part on its LSAM (large-scale additive manufacturing) 1020 using ABS pellets with 20 percent carbon fiber fill.
“After we printed it and machined it, they did their own testing on it based on cost-savings and things like that. They came back to us and said it saved around $50,000 compared to the traditional methods that they were using,” said Duane Marrett, vice president of marketing, Thermwood, Dale, Ind. “It took 16 hours to print and 32 hours to trim. Normally it would have taken six to eight weeks from start to finish for the way they were doing it before, and with the LSAM it took less than two weeks.”
The printing and trimming were both within the 1020, thanks to the machine’s second of two gantries, this one for a five-axis CNC router. “They can operate at the same time—while one is printing, the other is trimming,” Marrett said. The double-duty nature of the machine isn’t the only demonstration of the 1020’s versatility.
Thermwood has equipped the machine with three modes of printing—horizontally, vertically and on an angle, “which is our newest thing,” Marrett said. The angle layer printing uses a special table and a unique setup of the print head to dispense the material at a 45° angle. “That allows a lot of flexibility,” Marrett said.
For the marine industry, Thermwood 3D-printed a boat hull pattern for White River Marine Group with Techmer Electrafil ABS LT1 3DP. While the pattern wasn’t a head-to-head demonstration like that with General Atomics, the traditional method to make the part includes having to glue up a blank using wood or foam layers and then machining most of that material away, a process that could take months.
“This was a new design that the boat manufacturer gave us to print,” said Jason Susnjara, executive vice president of Thermwood, in response to comments on a YouTube video showing the boat hull printing.
The entire print, assembly and trim process required less than 10 working days to complete and used about $15,000 in materials. Once Thermwood 3D-printed the hull’s sections to near net, operators there machined the ends to flatten them, using a CNC machining center that’s part of the LSAM. They then used an epoxy to bond the sections together.
“Just like making a tool for about anything, if you start off with a big block of material, you end machining most of it away,” said Susnjara. “We offer CNC machining centers that do just that. 3D printing allows us to print an object that is slightly bigger than final size, requiring much less material removal. 3D printing is also quicker than machining. Generally we found that machining takes about 3 times longer than the print cycle, depending on geometery and finish.”
What governs print speed is essentially the cooling rate of the polymer being printed. Because the LSAM’s bead is a comparatively large 0.5″ (12.7 mm), the printer does its work in a room-temperature environment. The printed bead must cool enough to support the next layer, but must still be warm enough to fuse completely with it. This means there is a specific temperature range, which is different for each polymer. That amount of time is the fastest that a layer can be printed, regardless of its size.
Predicting the Future
Sciaky Inc., Chicago, whose welding and 3D printing technology are both powered by an electron beam, got its biggest order ever in early 2022. The order, which includes a customized EBAM 300 Series Additive Manufacturing System—the world’s largest electron beam directed energy deposition metal 3D printer—is for the Turkish Aerospace Industries’ (TAI) facility in Ankara, Turkey. TAI will use the Sciaky EBAM machine to print titanium aerostructures.
The contract between TAI and Sciaky also includes collaboration on a series of projects aimed at optimizing the customer’s use of the EBAM machine and its technology.
“In general, we work with the high-value materials like titanium, niobium, Inconel, tantalum—a lot of stuff that’s very specific to aerospace and defense, certainly things that are considered very strong and for environments that are very rugged; material that can stand up to things like space and defense,” said Jay Hollingsworth, public relations director for Phillips Service Industries Inc., Sciaky’s parent company.
In addition to doing 3D printing, the EBAM 300 can also be equipped to do electron beam (EB) welding for large-scale applications. This means TAI will have the advantage of combining EB welding and 3D printing functionality for applications that require both technologies.
“The AM system can switch over quickly to do the welding functions,” Hollingsworth said. “So you can build a nice, big aero structure and if the application needed to be joined to another part of the aircraft, or whatever you’re building, you can weld that part. It’s a two-for-one and there’s not many machines in the world that can do that.”
For quality and control, the EBAM 300 uses Sciaky’s Interlayer Real-time Imaging and Sensing System that can sense and digitally self-adjust metal deposition with precision and repeatability. This closed-loop control is the primary reason Sciaky’s EBAM 3D printing process delivers consistent part geometry, mechanical properties, microstructure and metal chemistry, from the first part to the last, according to prepared remarks from the company.
Hollingsworth pointed out the advantages 3D printing titanium parts has to offer customers like TAI. “For an industry like aerospace that is dealing with these really expensive materials, buying a huge chunk of titanium or a billet takes a very long time,” Hollingsworth said. “A lot of times somebody might order a billet of titanium and it might come from Russia, it might take 15 months to receive. For our system, there’s wire that’s abundantly available. And you’re not going to waste all the material as far as cutting it away. By the time you make the part [with a subtractive process] you’re wasting 80 percent of the titanium and that’s pretty expensive stuff. So here we’re speeding up the time to market as well as saving on the waste.”
Hollingsworth said there will be some machining on the part after printing, but described it as “minimal.” He noted other big manufacturers in the aerospace industry, including Airbus and Lockheed Martin, also have Sciaky’s EBAM technology. “We’re lucky that a lot of our processes have been approved for land, sea, air and space, and we’re working toward commercial aircraft adoption,” said Hollingsworth. “And certainly every one of the major airline manufacturers are looking at additive manufacturing and making their investments because they see the writing on the wall.”
Reducing Steps in Production
Meanwhile, Massivit 3D, Lod, Israel, has tweaked the chemistry of its UV-cure material to make it water-breakable for use in a new 3D printing process. Designed for use with the company’s Massivit 10000 model, also new, the slightly altered material, Dimengel 50, is used to print a shell for an isotropic composites mold.
“If you’ve ever seen someone lay down a form for a foundation, it’s kind of the same concept,” said Mike Clark, composites sales manager for North America. “An outside wall and an inside wall.”
During the process, eight to 10 layers of the “walls” are printed in 1-mm increments. Then a second printhead moves in and dispenses two-part tooling epoxy in the empty gap between the walls. The printing and pouring steps are repeated until the mold is complete.
“So you print some, you pour some,” said Clark.
The open time or the time the mixed materials take to achieve green strength is approximately 20 minutes. This open time allows the pour layers to blend, creating a true isotropic 3D-printed mold tool, Clark said. After printing and optional secondary heat treating, the part is soaked in water, which makes the Dimengel 50 walls break down. Once dry, the part can be sanded, buffed and polished.
“Mold manufacturers typically take between 19 and 25 steps to make a composites mold, but this takes it down to four steps,” Clark said. Refining the process also saves time, accounting for an up to 80-percent time reduction, a 90-percent reduction in labor and up to a 75-percent reduction in the total cost of tooling ownership, said Clark.
Advances in Material, Orientation, Speed
In addition to saving time, Clark noted the isotropic property of molds made on the 10000. “Ours is a solid material,” he said. “On the X, Y and Z-axes the coefficient of thermal expansion, the heat deflection temperature—all those characteristics are the same, regardless of orientation. In a traditional FDM printer you have to orient the part a certain way so the Z-axis doesn’t take the brunt of the load because the weakest link in a printed part is the lamination, the bonding [of the layers] or lack thereof.”
Massivit worked with ACS Hybrid Inc., and 3D Composites to print a tool for an aerospace part on a Massivit 1800 Pro that withstood 45 pulls in a thermoforming machine. Traditionally, the tools are made either of high-density foam or aluminum. “The high-density foam’s not going to last for 50 pulls,” said Clark. The metal tool would be far more durable, but in thermoforming you want a mold to retain some heat and aluminum is a conductor.
“If you made that same mold with the 10000 using CIM [cast-in-motion] 155 you’d get thousands [of pulls],” Clark said. Because CIM 155 is an insulator, it stays at temperature longer than aluminum. The 1800 Pro and two other models, the 1800 and the 5000, use the company’s original gel-dispensing 3D printing technology using an acrylic-based material.
In 2019, Massivit and Streetfighter LA, an auto parts and wide body kit maker, collaborated on a 2020 Toyota Supra MK5 Wide Body Kit, including 16 parts that were 3D printed on an 1800 Pro. The parts included body panels, the front lip, and the dynamic rear wing. The large printing volume of the 3D printer enabled pieces such as the front lip and rear spoiler to be printed in a single part up to 5′ (1.52 m) long.
This enabled making prototypes in 64 hours, which is dramatically faster than any traditional automotive prototyping methods such as cardboard, clay or foam. The availability of two print heads on Massivit 3D printing solutions allows for parallel production of two prototype parts. Multiple iterations can be quickly created, reducing time to market of accurate, symmetrical parts.
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